The dye-sensitized solar cell which was developed by Gratzel et al. is low in cost compared with solar cells each using a silicon semiconductor, and there are abundant raw materials needed for the production of the dye-sensitized solar cell, and hence, the dye-sensitized solar cell is expected as a next-generation solar cell.
The dye-sensitized solar cell includes: a transparent electrode substrate having a transparent conductive film; a porous oxide semiconductor electrode including a porous oxide semiconductor layer (mainly a TiO2 layer), which is formed on the transparent electrode substrate; a dye such as a Ru-dye, which is adsorbed to the porous oxide semiconductor electrode; an iodine electrolyte solution containing iodine; a counter electrode substrate on which a catalyst film and a transparent conductive film are formed; and the like.
There are used a glass substrate, a plastic substrate, and the like for the transparent electrode substrate and the counter electrode substrate. When the plastic substrate is used for the transparent electrode substrate, the resistivity of a transparent electrode film becomes large and the photoelectric conversion efficiency of the dye-sensitized solar cell lowers. On the other hand, when the glass substrate is used for the transparent electrode substrate, the resistivity of the transparent electrode film hardly increases, and hence, the photoelectric conversion efficiency of the dye-sensitized solar cell can be maintained. Therefore, in recent years, the glass substrate has been used as the transparent electrode substrate.
In the dye-sensitized solar cell, the iodine electrolyte solution is filled between the transparent electrode substrate and the counter electrode substrate. In order to prevent the leakage of the iodine electrolyte solution from the dye-sensitized solar cell, the peripheries of the transparent electrode substrate and the counter electrode substrate need to be sealed. Further, in order to effectively extract the generated electrons, a collector electrode (e.g., Ag or the like is used therefor) may be formed on the transparent electrode substrate. In this case, there is a need to overcoat the collector electrode and prevent a situation that the collector electrode is eroded by the iodine electrolyte solution. In addition, in the case of forming a cell circuit on one sheet of glass substrate, a partition wall may be formed between the transparent electrode substrate and the counter electrode substrate.